Hendron dialled 999, but the teenager had suffered a lethal overdose of a combination of mephedrone - known as "meow meow" - and GBL.

I bear in mind the anguish you feel over the death of your partner and the very moving letter from his mother in which, far from wanting you to be punished, she stands by youJudge Richard Marks QC

Police discovered Hendron's fingerprints on the jars and envelopes containing the drugs at his flat.

Hendron stood in the dock at the Old Bailey as Judge Richard Marks QC sentenced him to a community order, with 18 months' supervision and 140 hours' unpaid work.

Parkin, an Oxford graduate who won nine Sony awards for his work with the BBC but has now lost his job, was sentenced to a community order with 200 hours' unpaid work.

The judge told them: "I am not sentencing either of you for any criminal offence in connection with the tragic death.

"There was never any evidential justification for any such charge. Had it been the case your sentences would have been measured in years."

Judge Marks told Hendron: "I bear in mind the anguish you feel over the death of your partner and the very moving letter from his mother in which, far from wanting you to be punished, she stands by you."

Hendron's conviction may mark the end of a glittering career for the lawyer once tipped as a bright prospect in the Conservative party.

As a 17-year-old schoolboy, Hendron addressed the 1998 Conservative Party conference calling for the re-introduction of corporal punishment.

He acted for Tory MP Nadine Dorries when she was accused of smearing a rival during the 2015 election campaign and other clients include the Earl of Cardigan and The Apprentice winner Stella English.

Henry Hendron admitted he bought the drugs for himself and his partner and also to sell on to friends at cost priceCredit:
Christopher Pledger for The Telegraph

Hendron admitted he bought the drugs for himself and his partner and also to sell on to friends at cost price.

Prosecutor Martyn Bowyer said: "Both these drugs are commonly used in the gay chemsex scene.

"Such a combination, particularly if alcohol and cocaine are involved, has a medically proven effect on the heart rate and blood pressure.

"The tragic death of Miguel Jimenez goes only to highlight the dangers of abusing them."

GBL, which induces feelings of wellbeing and intensifies sexual arousal, is used legitimately as an alloy cleaner and solvent and "was never intended for human consumption", said Mr Bowyer.

Mephedrone is a synthetic drug with similar effects to amphetamines and, like GBL, stimulates the heart and can increase blood pressure.

Police found a total of 82g of methodrone in plastic bags inside envelopes in a cupboard and 482ml of GBL in jars after being called to Hendron's flat.

Hendron, who charges up to £1,750 per day for his legal services, at first denied buying and supplying the drugs but admitted using them with Miguel, whom he met in August 2014.

Barrister Henry Hendron, centre, arrives for his sentencing hearing at the Old BaileyCredit:
Christopher Pledger for The Telegraph

He told police that after a day at court he spent the evening of January 19 with Miguel and a friend at his flat.

Hendron claimed he warned Miguel about his drug use before they went to bed.

"When he awoke their friend had left and he became aware Miguel was not moving," said Mr Bowyer. "He saw blood and vomit around his face and dialled 999.

"He was highly distressed and stated he had discovered the apparently lifeless body of his partner with whom he lived.

"Paramedics attended the scene and pronounced him dead. A postmortem concluded he had died of a lethal combination of drugs including GBL and Mephedrone."

On his arrest, Parkin claimed he bought the drugs from a Brazilian man, keeping 250ml of GBL for himself and selling another litre to Hendron.

"He later admitted to officers he was struggling with addiction to drugs," said Mr Bowyer.

Parkin, who has a previous caution for possession of mephedrone, presented references from the controller of BBC Radio 3 and the British Embassy in Dubai to the court.

His barrister, Dominic Bell, said that since losing his job he is "devoting all his attention to DIY".

Alexander Parkin, an Oxford graduate who won nine Sony awards for his work with the BBC, arriving at courtCredit:
Christopher Pledger for The Telegraph

Hendron has three previous convictions for drink driving.

His barrister, Timothy Cray, said: "He is well aware that public opinion and his professional body may well take a far wider view of his personal responsibility for events that led to the death of Miguel."

Hendron, of Temple, City of London, admitted possession of the Class B drug methedrone and the Class C drug Gamma-butyrolactone (GBL) with intent to supply.